The treatment of chronic and non-chronic states of pain is of great importance in medicine since pain is clinically one of the basic symptoms. There is currently a worldwide demand for additional pain treatment which is not exclusively opioid but has a good efficacy. The urgent need for action in respect of patient-relevant and target-oriented treatment of chronic and non-chronic states of pain, this being understood as meaning successful and satisfactory pain treatment for the patient, is documented in the large number of scientific works which have recently appeared in the field of applied analgesia and fundamental research into nociception.
Conventional opioids, such as e.g. morphine, have a good action in the treatment of severe to very severe pain. However, their use is limited due to the known side effects, e.g. respiratory depression, vomiting, sedation, constipation, addiction, dependency and development of tolerance. They can therefore be administered over a relatively long period of time or in relatively high dosages only with particular safety precautions, such as e.g. specific prescription instructions (Goodman, Gilman, The Pharmacological Basis of Therapeutics, Pergamon Press, New York 1990). Furthermore, they are not very effective for some states of pain, in particular neuropathic pain.